BMW's R&D board member Herbert Diess is ecstatic. "It is even more elegant than the coupe," he says of the 4 Series Gran Coupe (Official Thread) on the roof terrace of the Grand Hotel Domine, just across from the Guggenheim Museum in Bilbao. Exterior chief designer Karim Habib agrees. The latest addition to the F3x architecture was conceived before he returned to BMW after his relatively brief stint at Mercedes-Benz, but he seems thoroughly happy with the work of designer Won Kyu Kang.

Possibly more than any other BMW, the existence of the 4 Series Gran Coupe is justified by aesthetics. It fits into a niche that few would have thought even existed - between the 3-series sedan, whose wheelbase it shares, and the ungainly 3 Series Gran Turismo with its tall roof and longer wheelbase. The 4 Series Gran Coupe has a bit more cargo room than in the 4 Series sedan, and its trunk is accessible through a liftgate. But most importantly, it looks better than both aforementioned models. (It would look nearly perfect without the garish, if supposedly functional "air breathers," and the badge glued to the rear quarter window.)

BMW isn't shy to admit that the Audi A5 Sportback was the inspiration for the 4 Series Gran Coupe. But the Audi - a close relative of the A4 - is not offered on the US market. Mercedes-Benz doesn't even make a hatchback. Here, BMW has a niche of its own, for the time being.

Perhaps that's the reason why BMW doesn't feel compelled to bring a flurry of variations to this market. In Europe, the hatchback is offered as the 420i (2.0-liter four, 181 horsepower), the 428i (2.0-liter four, 240 horsepower), 435i (3.0-i6, 300 horsepower), and with two variations of the 2.0-liter four-cylinder turbodiesel (418d, 141 horsepower; and 420d, 181 horsepower). It's an open secret that a 430d and a 435d will follow. Rear-wheel-drive and all-wheel-drive variations are available, and most of them can be specified with a six-speed manual or the ZF 8HP eight-speed automatic. Not so in the US. Here, the brand has pre-selected the three presumably most popular variations: The 428i with rear-wheel drive and all-wheel drive, and the 435i with rear-wheel drive. The slushbox is standard and can't be substituted with a stick.

We were able to sample the 428i in the twisties near Bilbao, fitted with the M Sport package, and painted in Estoril Blue - a classic M color that doesn't quite seem to fit the character of this relatively large hatchback. The numbers are impressive: BMW claims it can reach 60 mph in a mere 5.7 seconds. Unless hampered by all-season tires and the 130 mph governor they require, the 428i Gran Coupe can reach a remarkable 155 mph - which is testament to its superior aerodynamics.

But you wouldn't believe it from behind the wheel. The soundtrack of the N20 engine is nondescript, mid-range performance could be better. The automatic transmission is eager and quick, but it doesn't quite match the ultra-quick shifts of Audi's - or the M3's - dual-clutch box. Switching between the driving modes helps things, but even "Sport Plus" can't turn the four-banger into an inline-six.

But it can help the chassis to dance. "Sport Plus" doesn't switch off the stability control entirely - at all. But it does allow slight drift angles, without scaring anyone. And it helps this relatively large hatchback turn into corners with surprising alacrity. This car proves there is simply no substitute for a rear-wheel drive platform, and it doesn't take a lot of effort to get its tail to rotate into a corner. In lesser driving modes, the BMW doesn't excite, but it is a great high-comfort, long-distance cruiser.

And that's a good thing, as there is ample room both up front and abaft - enough so, possibly, to make buyers of the 5 Series think twice. The rear seats can be folded down, which increases trunk space from 17 to 46 cubic feet. Inside, there are few differences between the 3 Series and the 4 Series; the dashboard is shared, but the door trim is unique to the Gran Coupe.

We were not able to sample what we suspect will be our favorite 4 Series - the 435i. Its turbocharged straight-six supplies the extra bit of performance and sound that will set a BMW apart from the competition. It'll also be the most powerful Gran Coupe; our company sources tell us that we shouldn't hold our breath for an M4 Gran Coupe.

Given that BMW nonchalantly charges a premium of $25,000 to $30,000 for a 6 Series Gran Coupe over a 5 Series, the 4 Series Gran Coupe may be considered a bargain: It comes in at just a few grand over a comparable 3 Series. The 428i Gran Coupe will be sold from $41,225 upwards, with xDrive all-wheel drive as a $2,000 option; the 435i Gran Coupe costs $46,725 (see the 2015 price/order guide). If that seems cheap, rest assured that BMW will offer the usual array of packages and options. For special requests, as always, BMW's "Individual" branch is happy to help out.